Frequency shift key (FSK) and phase shift key (PSK) demodulators typically make use of some technique for determining a phase of a complex signal. The hardware for implementing some phase determination techniques can be relatively complex, with a relatively large bit-width. Some of the techniques are vulnerable to frequency offsets due to the frequency drift between the transmitter's and the receiver's local oscillator and some have a quadratic dependency on amplitude variation. Some of the approaches for determining the phase of a complex signal use lookup tables, which need a relatively large amount of memory space.